PIR Over Wireless Channels: Achieving Privacy With Public Responses

TL;DR

This paper introduces a novel randomized lattice coding scheme for Private Information Retrieval over noisy wireless channels, ensuring user privacy even when servers can eavesdrop on each other's responses.

Contribution

It proposes the first PIR scheme that jointly addresses privacy, channel noise, and server eavesdropping in wireless environments.

Findings

Positive PIR rate achievable despite stronger eavesdropper channels

New lattice coding scheme effectively protects privacy in noisy wireless channels

Addresses a gap in PIR research for shared wireless mediums

Abstract

In this paper, we address the problem of Private Information Retrieval (PIR) over a public Additive White Gaussian Noise (AWGN) channel. In such a setup, the server's responses are visible to other servers. Thus, a curious server can listen to the other responses, compromising the user's privacy. Indeed, previous works on PIR over a shared medium assumed the servers cannot instantaneously listen to other responses. To address this gap, we present a novel randomized lattice -- PIR coding scheme that jointly codes for privacy, channel noise, and curious servers which may listen to other responses. We demonstrate that a positive PIR rate is achievable even in cases where the channel to the curious server is stronger than the channel to the user.